1. Field of the Invention
The subject invention relates to novel water dispersible or water-soluble copolymers which contain at least one UV-absorbing monomer and one hydrophilic monomer component. The copolymers may optionally contain a hydrophobic monomer component (i.e., if you have a water-soluble UV absorber, then you need hydrophobic groups to ensure it adsorbs). These copolymers may be used in fabric care compositions and provide anti-fading and soil release benefits. Because of their UV absorbancy, such copolymer could also be used in sunscreen compositions. The copolymers may also be used in other compositions such as may be recognized by those skilled in the art.
2. Prior Art
UV light induced fading of fabric is a major concern to those residing in areas of high solar intensity. A fabric care agent which could provide protection from solar ultraviolet radiation and thereby retard the rate of garment fading would therefore prove most useful to consumers living in tropical and sub-tropical climates.
To the applicants, knowledge, the use of an otherwise water-insoluble UV absorbing monomer in combination with a hydrophilic monomer (which both delivers the copolymer into an aqueous system and also provides soil-release effect) is unknown.
More particularly, it is known, for example, that poly(ethylehe terephthalate/poly(ethylene glycol) copolymers absorb onto hydrophobic surfaces to confer soil release properties (U.S. Pat. No. 4,702,857 to Procter & Gamble; U.S. Pat. No. 4,569,772 to Colgate Palmolive, and U.S. Pat. No. 3,959,230 to Procter & Gamble). These materials are believed to function by hydrophilicly modifying a hydrophobic surface such as oily soil on fabric or polyester fabric itself, deterring deposition of hydrophobic soils including body sebum. The poly(ethylene terephthalate) unit is believed to seek and adhere to the hydrophobic surface; the poly(ethylene glycol) portion is felt to give hydrophilic character to the fabric surface as well as aid the polymer in transfer through the aqueous medium.
In addition, it is also well known that UV-absorbing agents such as p-aminobenzoic acid (PABA) and its derivatives have been used for nearly half a century as UV screening agents (N. A. Shaath in "Sunscreens: Development, Evaluation, and Regulatory Aspects," N. J. Lowe and N. A. Shaath, Eds., Marcel Dekker, Inc., New York, 1990).
UV sunscreen agents such as PABA, however, are generally water-insoluble and there appears to be no teaching of combining such agents in carriers such that they may be used, for example, in fabric cleaning compositions.
U.S. Pat. No. 4,153,744 to K. H. Remley teaches the use of a tetrakis(hydroxymethyl)phosphonium salt to impart resistance to UV light-induced shade change to vat-dyed cellulosic textile materials. These compounds are unrelated to the copolymers of the invention. Further the process for delivering the compound is time-consuming and requires ammoniation of fabric followed by treatment with glacial acetic acid/hydrogen peroxide.
U.S. Pat. No. 4,788,054 to R. J. Bernhardt, et al. teaches the use of N-phenylphthalisomides as ultraviolet radiation absorbers for cotton, wool, polyester, and rayon fabric. Again, these compounds are unrelated to the copolymers of the invention. Further, an aqueous sulfuric acid vehicle is required for deposition.
In P. C. Crews et al., Text. Chem. Color, 19 (11): 21 (1987), the use of 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, and 2-hydroxy-4-methoxybenzophenone as UV absorbers for museum textiles is taught. These compounds differ from those of the invention. Here, potentially carcinogenic perchloroethylene is required as the vehicle. Water-soluble 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid was also shown to reduce dye fading of museum textiles, but with significant yellowing of fabric.
B. Milligan et al., Polym. Degrad. Stab., 10(4):335(1985), teach the use of 2,2'-dihydroxy-4-4'-bissulphobutyloxybenzophenone as a water-soluble ultraviolet light absorber for retarding the photo degradation of wool, but its synthesis requires the use of butanesultone, a suspected carcinogen.
None of the above-identified references make mention of soil release potential or teach materials that can be delivered in home laundry care.
U.S. Pat. Nos. 3,888,965, to S. L. Kwolek; 3,699,085 to T. A. Johnson; and 3,600,350 to S. L. Kwolek teach the synthesis of poly (.rho.-benzamide) via homopolymerization of 4-aminobenzoylchloride hydrochloride, and German Patents Ger. Offen. 2,351,892 and 2,538,143 teach the synthesis of poly (.rho.-benzamide) via homopolymerization of 4-aminobenzoic acid in the presence of phosphates. In each of these references, the resulting poly PABA is insoluble in water, dilute acid, dilute base, and most organic solvents, rendering its application as a UV-absorbing polymer for fabric or skin care useless.
Japanese Patent Jpn. Kokai Tokkyo Koho 80,137,217 (Unitika Ltd.) teaches the synthesis of poly(ethylene terephthalate)/poly(.rho.-benzamide) copolymers for high modulus automobile tire cords. I. F. Osipenko, et al., Vesti Akad. Navuk BSSR, Ser. Khim, Navuk; 1:105 (1980), teach the synthesis of poly(ethylene terephthalate)/poly(.rho.-benzamide) copolymers and that the incorporation of .rho.-aminobenzoic acid into poly(ethylene terephthalate) improves fiber-forming properties and dye ability. Neither of these patents or publications mention the use of the poly(.rho.-benzamide)-based materials as UV-absorbing agents or soil-release agents, nor do these disclosures mention that the poly(.rho.-benzamide)-based materials are water-soluble or water dispersible.
In each of the above-identified references, the compound used differs from the copolymer of the invention, there is no teaching that a UV-absorbing monomer can be delivered in an aqueous (e.g., fabric care) system, and there is no teaching or suggestion that the UV-absorbing monomer can be used in a copolymer which imparts fade-resistance or soil-release properties.
As such, there is a need in the art for novel copolymers comprising a UV-absorbing monomer copolymerized with a hydrophilic monomer which allows the UV-absorbing polymer to be delivered in an aqueous system and simultaneously provides soil release benefits.